becker



J. BECKER.

OPTICAL FOCUSER.

APPLICATION FILED AUG.16| 1916.

'1 ,3 1 9 ,750 Patented Oct. 28; 1919.

' 2[5HEETS5HEET 1- 21 R91 1; W5

mtneweo 1. BECKER.

OPTICAL FOCUSER. APPLICATION FILE D M IGJG. I916.

Patented Oct. 28, 1919.

2 SHEETS-SHEET 2 Mn 8 n a W WM August 22, 1916; Case UNITE STATES JOSEPHBECKER, OF WASHINGTON, ms'rmcror CoLUMBIA,- AssIGNoR Y'ro EASTMAN KODAKCOMPANY, OF RQOHESTER, NEW YORK, A CORPORATION OF NEW; YORK.

OPTICAL rOCU'sEn.

To all whom'z't may concern:

Be it known that I, JosEPH BECKER, a citizen of the United States,residing at Washington, In the Distri ct of Columbia, have invented anew and useful Improvement in Optical Focusers, of which the fol-,lowing is a specification. My present application is identified forconvenience of re erence as Case Am. v

y present invention relates to optical focusers of the type showing atleast one movable image, and it consists in means for varying, quickland at will, the focus-indicating position 0 such movable image.

y present invention, all focusers of the mirror type shown in my Case A,now Patent 1,178,474, issued April 4, 1916 and it, therefore, likewiserelates to all focusers disclosed in my other applica-v tions orpatents, as follows:

Case B, now Patent 1,17 8,475, issued April 4, 1916; Case C, now. Patent1,178,476, issued April 4, 1916; Case D,now Patent 1,190,623, issuedJuly 11, 1916; Case F, now Patent 1,195,947, issued August 22, 1916 Case'J, now Patent 1,210,136, issued December 26, 1916; Case W, now Patent1,195,948, issued Ag, now Patent 1,240,651, issued September 18, 1917;Case Ah, now Patent 1,210,134, issued December 26, 1916; Case Ai, SerialNo. 88,619, filed April'3, 1916; Case Ak, continued as Case Ax and nowPatent 1,240,788, issued September 18, 1917; and Case AL, now. Patent1,210,135, issued Dec. 26, 1916.

In the present embodiment, my inventlon consists more'specifically inmeans for varying the focus-indicating posit on of such movable image,quickly and at will, from the focus-indicating position of coincidenceseen in Fig. 8 of my said Case A, or in Fig.-

11 of my said Case B, toa focus-indicating position of mere alinement asin F 1g. 14 of my said Case B, so that the operator may quickly and atwill, use any preferred one or even both of these focus-lndlcatmgpositions, on the same given 01)]80610 be focused on.

, Specification of Letters Patent. Application filed August 16, 1910.Serial No.

preferably done, Without tical element, by sli htly and suitably in-'clining one of the therefore, relates to camera of. the

' slide,in and out,

This change in the focus-indicating position may be produced in-manydifferent ways involving the use of auxiliary optical devices such as anoflsetting prism, but is is ocuser mirrors onits support as alreadyindicated in my said Patented-Ocfl28, 1919.

any additional op.-

Case B, page 4, "lines 52 to 81, where the.

mirror so inclined is scribedin my said Case B.- -In the accompanyingdrawings, which illustrate a focus-indicating position changer actuallyconstructed and used by me more than ten years ago;

Figure 1 is a fractional face view, and

Fig. 2' is'a fractional side view, of. the camera and its focuser.

a pivoted object mir .ror; or, as'already indicated in O my said aseFig. 3 is aplanjof the main and the auxplates used in iliary base themount of the pivoted mirror.

Fig. 4 isa vertical, longitudinal, section of the pivoted mirror and itsmountin comsave as to that partof Fig. 6 which is lettered 96 to 99, and

plet-e assembled relation;

which is omitted in the present Fig.4 for clearness. 3

:Fig. 5 is an inside elevation of a brace that serves to hold and cla pthe pivoted mirror in fixed relation to the auxiliary base plate of itspivoted mount- Fig.6 is a plan of the lower or main base plate of themirror mount and of the cylindrical cam, used to lift, and more or-lessincline, the auxiliary base plate on the line any as pivotal axis. Thecamera,

usualconstruction comprising:' a box 23; a opens and locks in serve ascamera bed; a bar. 50 adapted to on the bed 19; and a rechinged cover19. which horizontal position to .95

. 9 0 i Fig; 1, is1a folding bellows I The optical elements of thefocuser are substantially the same as in my said Case C, and thereforecomprise: either a single or compound eccentric divergent-lens L; afixed prism P cemented on the outer face of lens L; and a mirror Cpivoted to turn on the horizontal shaft 65, under the action of a camplate K. Thiscam plate K is adjustably fastened to the bracket 66 byscrews 67,.68, and acts directly on the tail-plece 69 of the pivotedmirror to lift the same in opposition to the downward pressure of spring70.

The position of the operators eye, indicated by E, is, determined, as inmy said Case J, by providing separate and independent means fordetermining its position first horizontally, or in azimuth; then,vertically or in altitude. Its position in azimuth 1s fixed by theimaginary vertical plane wh ch passes through the vertical meridian linemarked on finder lens L and through the middle point ofa peep 25 whichis cut into the upper edge of the box 23; while its position in altitudeis determined by raising the eye, in the said vertical plane, until thereflected image of-a horizontal wire 24 is seen at the middle of the eyemirror P.

So far all parts are substantially as in my said Case C and coiiperateto produce a vertically movable image in prism P, whose vertical pathsecures a focus-indicating position of coincidence, or only ofalinement, accordingly as the mirror 0 is or is not adapted to bebrought into exact parallelism with the reflecting face of prism P.

The novel structural features which involve the present invention areall contained in the mount of the pivoted mirror C.

This mount comprises a main base plate 80, Figs. 2, 3, 4, and 6, whichis rearwardly extended to form the before-mentioned tailpiece 69.

The forward end of plate 80 is provided with two V-bearings 81, 82,which bear and turn on the enlarged ends of the fixed shaft 65. A hook83 passed upwardly through a hole 84 (Fig. 6) and then downwardlythrough hole 84", serves to connect this base plate 80 with the spring70, which is thus made to keep the two V-bearings 81, 82 in contact withshaft and the tail-piece 69 in contact with the cam plate K,substantially as explained in my said Case G, except that base the twoholes 84, 84-here shown, serve to positively keep the hook 83 in properposition to admit the spring while the parts are being assembled. I

The base plate 80, in the present arrangement, has riveted thereon twofixed conical studs 85, 86, which determine the auxiliary pivotal axismy, Fig. 6, of the pivoted mirror.

On these studs 85, 86 is mounted the auxiliary base plate 87 which, asseen in Fig. 3, has a small round hole 88, to engage with stud 8'5, andan elongated slot 89,, to engage with stud 86.

The third resting point of the auxiliary plate 87 is formed by a screw90, shown dotted in Fig. 3, and which passes up through a threaded holeformed in the main late 80.

A olt 91, Figs. 3, 4 and 6, with nut 92, Fig. 4, spring 93 and washer94, serves to keep the auxiliary base plate 87 in firm contact withits'three supporting points 85, 86 and 90.

The auxiliary plate 87 does not bear directl on screw 90, but isseparated therefrom by an arcuate wedge or cam 96, Figs. 1, 2 and 6,which is carried by a radial arm 97, Fig. 6, pivoted on a cylindricalpart of stud 86, and actuated by means of the sec- 0nd radial arm 98,whose outer endis bent downwardly and coiled to form a handle 99.

The extreme angular positions that may be occupied by arm 98 aredetermined by radial abutments 100 and 101, Fig. 6, formed in the mainbase plate 80. The arcuate wedge 96 is thickest at its rear radial end96, Fig. 6; and it is thinnest at its forward radial end, near theterminal point of leader 96 in Fig. 6.

When, therefore, the handle 99 is held pressed firmly against the rearstop 100 of the main base plate 80, it is the thinnest usable part ofthe wedge that rests on the I end ofscrew 90; and when the handle 99 isheld pressed in contact with the forward step 101 of main base plate'80, it is the thickest usable part 96 'of-the wedge that rests on. theend of the screw 90.

The auxiliary base plate 87 being on top of the wedge 97- canaccordingly be raised and lowered very quickly and at will, withreference to the main base plate 80, about axis wy,-Fig. 6, as itspivotal axis, from onev extreme relative angular position to theopposite extreme (relative angular position, through all intermediatevalues, by simply acting on'handle 99.

The auxiliary base plate 87 has its forward end provided with pOckets1.02, 103, to admit and hold the lower corners of mirror C,-and its rearend is recessed at 104, 105, to admit and hold the feet 106, 107,- Fig.5,

- formed on a brace 108, whose upper end. is

edge of this opening 113, provides the play room required for bolt 110,and insures that the-pull of the bolt on nut 112 shall be in alinementwith the lower inclined bearing edge of opening 113.

' Operation.

The cam K actsto cause the image seen by reflection in C and P toriseand fall along a vertical path, and, this vertical path can'beoflset horizontally by changing the inclinationof the auxiliary baseplate87 on the main base plate 80.

offset in either one The device is adjusted by acting on screw 90. Toadjust, wedge 96 is first drawn back as far as permitted by the rearstop 100 andthen, using a vertical or plumb line astest object, isturned as much as may be necessary to secure zero ofi'set in thevertical path of .the movable image; that is to say the movable imageof. thev plumb. line must be offset horizontally by means of screw 90-until it. is brought into coincidence with the immovable image of thesame vertical or plumb line,

If now the wedge 96 is pushed-in, it will lift. the mirror C, about axismy, and it will ofl'set the path of the movable image seen in P towardthe outer wall 62 of the focuser, and this ofl'set can be made as smallor as large as desired within the extreme limits imposed by the twopositive sired. The-range from zerov offset up, will gerferally provesuflicient.

-NOTE 1.The. ofl'set focus-indicating position is so much more usefulthan the coincident focus-indicating position, that the operator willgenerally keep it as the normal focus-indicating position. NOTE 2..Wherethe focuser is of the twoimage type seen in Fig. '39 of my said Case A,a change in the focus-indicating position may easily be made byproducing an or both of the two 1mages. I

No'rn -3 Where the focuser is of the two or lowered,

8, where the comblike stops I 100 and 101 in the base plate 80, Fig. 6.

lower, to produce p a minimum offset that is negative, if deerativecombinations,

. mallyfixed, the change in the focus-indicatmg position may be made byoffsetting the said stationary image.

Norr. 4.When screw 90 is either raised it really changes the two extremepositions of the auxiliary plate 87, that is to say: If it depressesthelowest position of'the auxiliary plate 87 one-half degree, forinstance, it must'simultaneously depress the highest position by thesame I amount, but the exact value of this upper limit is not important.

NOTE 5.I am aware that Barr Stroud, prior to 1896,.were quite familiarwith thefactthat a very small single object point cannot practically beutilized to and produce two simultaneously visible and distinguishablepartial point images; and that they. overcame the difli'culty to theirentire satisfaction, for naval range-finding purposes, by the use of acylindrical-lens system called-an astigmatizer. See the thirtyfour-lineparagraph entitled Astigmatirser in Institution of Mechanical Enginears,Proceedings, London, January, 1896, pages 46, 47. "This Barr and Stroudsolution, however, could not satisfactorily be used in combination witha camera finder, because it mutilates the Whole image beyondrecognition, as seen: first, in their Fig. 26, plate 8, Where the lineeffect produced on'a single small object point is Shown, and secondly,their Fig. 27, plate effect produced a series of small object points isshown.

NOTE 6.My said Case A, page 20, lines 104 to 108, lays down the generalprinciple that when a camera, having an optical focuser, is also.provided with the usual' focusing or distance scale,.a s shown in Figs.82, 33 and especially in Fig. 57* of said Case A, the device is not onlytelemetric inprinciple, but it furthermore becomesjin fact. a rangefinder. Such range finder, that of the said Fig. 57-", for instance,would how: ever, still be complete as a range finder, afterremoval ofthe camera objective, and, therefore, my present invention is not lim--ited to photographic cameras.

NOTE 7 .-When, therefore, in View of Note 6,- above, my present pathoffsetter is apphed to the f-ocuser of my said Case 13, Where the camerais already provided with a focusing ordistance scale, and the 0& settersimplyserves to'shiftfrom the series of image phases'shown in Figs. 11to 13 of'said CaseB, to the series shown in its Figs. 14 to 16, theresultant assemblage must virtually comprise four different opto wit:(1) the twoelemerit combination of camera and distance scale, which isoperative, without the focuser, in the ordinary way, for focusing on anobject whose distance is known; (2) the two element combination offocuser and distance scale which is operative, without the camera lens,as a .simple range finder; (3) the two-element combination of focuserand camera, which is operative without the scale for focusin by changingthe depth of the camera "to ring the two distinct retinal images intotheir focus indicating position; (4) three-element combination offocuser, camera, and distance scale which is operative for exposing aneither approaching or receding moving object, at the instant when it issituated at a predetermined distance from the camera, such result beingobtained in two steps, to wit: first, by using the scale to set thecamera in focus for the desired distance; and, secondly, by waiting forthe instant when, the, in such case, relatively moving retinal images ofthe moving object, have automatically .come into the focus indicatingrelative position. I

My present invention is therefore directly applicable to all military,naval and other range finders proper of the special and now morecommonly used duplicate image type; as a substitute for the Barr andStroud astimatizer of Note 5 above, over which it has the followingadvantages, to wit: first,-that it can be applied to any standardmilitary or naval range finder without adding. a single optical elementto the optical combination as it is now manufactured, when made withoutan astigmatizer secondly, that its presence, when set for zero offset,vdoes not m any way modify or interfere with the normal action and useof the' range finder; thirdly, that it is quickly thrown either into useor out of use, by a simple motion of the hand fourthly, that by a morecareful motion of the hand, executed while observing, the lateral offsetof the range-indicating position of the two images can be varied to anydesired degree that 7 maywprove most effective in the particular case 8.My screw 90 controls what Barr and Stroud have defined (page 54, lines 6to 25, of their paper cited in Note 5 above) as Y the halvingadjustment; and it therefore corresponds, in function, to the Barr andStroud screw H, Fig. 40, plate 12.

What I claim as my invention and desire to secure by Letters Patent is:

1. The combination with a focusing camera comprising an optical focuserof the type adapted to form at least one movable image, and having meansfor offsetting the relative path of such movable image to permit ofsecuring different desirable characteristic focusindicating positions;of a movable mechanical element adapted to control such gem-pm use ofthe focuser, for quickly changing from one of the said characteristicfocusindicating positions to another; and positive stops to determinethe free range of mo tion of such movable-mechanical element.

3. The combination with an optical focuser of the type adapted to formwith rays from an object point to be focused on at least one movableimage having a characteristic focus indicating position, said. focusercom rising a part that is movable be tween de nite limits and whosemotion is adapted to offset the path of the said movable image; ofadjustable means for fixing one of said limitsto permit of securingexact zero offset.

4. The combination with a focusing camera comprising an optical focuserof the type adapted to form two relatively movable retinal images havinga normal characteristic focus-indicating relative positi0n;-- of meansfor changing said normal characteristic focus-indicating relativeposition into a different or abnormal but focally equivalentcharacteristic focus-indicating relative position; said means comprisintwo different adjustments, one distinguis ed as fin'e orslow, the otheras coarse or rapid; that which is relatively fine or slow being ada tedto determine a, positive but adjustable imit to that which is relativelycoarse or rapid.

'5. The combination with a focusing camera comprising an optical focuserof the type adapted to form two relatively movable retinal images havinga normal characteristic focus-indicating relative osition; of means forchanging said norm characteristic foens-indicating relative positioninto adifferent or abnormal but focally equivalent characteristicfocus-indicating relative position; said means comprising a; manuallymovable mechanical element adapted to be moved for changing the natureof the said characteristic focus-indicating relative position; and apositive stop for limitin' its extent of motion in the direction thateads to the said normal characteristic focus-indicating position.

6. The combination with a focusing camera comprising an optical focuserof the nd adapted to be set to secure retinal images having a normalcharacter istic focus-lndicating relative position; of

means for changing said normal character istic focus-indicating relativeposition, a different or abnormal but focally equivalent characteristicfocus-indicating relative position; saidm'eans comprising a manuallymovable mechanical element adapted to be moved for changing the natureof the said characteristic focus-indicating relative posiiting itsmotion in the direction that leads to the said abnormal characteristicfocusindicating position.

7. The combination with a focusing camera comprising an optical focuserof the 2Q t pe adapted to form two relatively mova le retinal imageshaving a normal characteristic focus-indicating relative position; ofmeans for changing said normal character-. istic focus-indicatingrelative position into rent or' abnormalbut focally uivalentcharacteristic focus-indicating re ative position means comprising amanually movagble mechanical element; a positive sto for limiting itsextent of motion in the irection that leads to the said normalcharacteristic focus-indicating position; and a secnormally fixed butadjustable element a slight desirable change in the nature of saidnormal charac- 85 teristic focus-indicating relative position.

8. The combination with an optical instrument of the type adapted toform two relatively movable retinal images of the ob ect point to beobserved, said images hav- 40 ing a normal characteristic relativeobservation position; of means for changing said characteristic relativeobservation position into a different or abnormal but equivalentcharacteristic relative observation position; said means comprising amanually movable mechanical element adapted to be moved for changing thenature of the'said characteristic relative observation position; and apositive stop for limiting its extent-0f motion in the direction thatleads to the said normal characteristic relative observation position.

9. The combination with an optical in-- strument of thetype adapted toform two retinal images of an object point to be observed with saidinstrument, and comprising a relatively movable element whose relativemotions are adapted to impart to said two retinal images a relativedisplacement such as to cause the said two retinal images to passthrough a normal characteristic relative position which indicates thatthe said instrument has properly been set for the object point thatisbeing observed"; of means for changing said normal characteristicsetindicating relative position into a difierent or abnormal butindicatively equivalent characteristic set-indicating relative posi--tion; said means comprising a manually movable mechanical elementadapted to be moved for changing the nature of the said characteristicset-indicating relative position; and a positive stop for limitin itsextent of 1110131011 in the direction that eads to the said normalcharacteristic set-indicating relative position.

JOSEPH BECKER.

